Motion transmitting remote control assemblies are provided in many applications for transmitting motion in a curved path by a flexible motion transmitting core element slidably disposed in a conduit. Although such assemblies are not limited to use in the automotive environment, typical automotive applications include the control of automatic transmissions, clutches, accelerator, and cruise controls, HVAC vents, and the like. The conduits of such assemblies are supported at their two opposite ends on a bulk head, fire wall, engine bracket, transmission bracket, or other support fixture in the vehicle. In many applications, the support fixture vibrates while the automobile is in operation, particularly when the support fixture extends from the engine or transmission. A problem arises when vibrations in the support fixture are passed through the cable via an end fitting on the conduit.
There are assemblies in the prior art where vibration dampening means are used to isolate vibrations which normally pass from the vibrating support fixture through the end fitting of the conduit to the core element such that the vibrations are effectively attenuated or dampened. Examples of such prior art vibration dampening means may be found in U.S. Pat. No. 4,406,177 to Bennett et al., issued Sep. 27, 1983 and U.S. Pat. No. 4,726,251 to Niskanen, issued Feb. 23, 1988, both assigned to the assignee of the subject invention and the disclosures of which are hereby incorporated by reference. These assemblies include an end fitting disposed around one end of the conduit. The end fitting is surrounded by an outer casing which attaches to the support fixture to support the one end of the conduit on the vibrating support fixture. A resilient vibration dampener is disposed between the casing and the end fitting on the conduit for providing noise and vibration isolation therebetween. In this manner, the casing is completely insulated from the conduit by the vibration dampener, and the vibration dampener is held in place by the casing.
As perhaps best shown in U.S. Pat. No. 4,348,348 to Bennett et al, issued Sep. 7, 1982 and assigned to the assignee of the subject invention, the disclosure of which is hereby incorporated by reference, vibration dampeners are typically insert-molded onto the inner end fitting of the conduit. In a different plastic injection mold cavity, the casing is later overmolded about the vibration dampener. Although this practice is efficient and yields cable assemblies of consistent high quality, there are nevertheless some drawbacks.
One disadvantage of overmolding the plastic casing about the vibration dampener is that only relatively high durometer elastomeric materials can be used. It will be readily appreciated by those skilled in the art that lower durometer materials are often preferable and will, in general, provide increased vibration dampening. Also, the practice of insert molding one integral vibration dampener having a uniform durometer is somewhat restrictive because it may be beneficial in some instances to provide a multi-durometer vibration dampener. However, present techniques for molding multi-durometer members require multiple molds which can be very-expensive. In addition, the overmolded vibration dampeners are permanently encapsulated in the casing, which prevents repair or replacement of defective or worn vibration dampers. This same fact also results in compounded inventory commitments whereby otherwise identical cable assemblies having different durometer vibration dampeners must be stored. Thus, because the vibration dampener can not be accessed for exchange of a different durometer vibration dampener, an inventory of cable assemblies of each useful durometer must be maintained.